There is known an uninterruptible power supply provided with a storage battery for continuing to provide power from the storage battery to equipment connected thereto for a predetermined time without causing power failure even when the power from an input power source is interrupted. Techniques are developed for extending such a power supply into each consumer and supplying power to the consumers when an abnormality occurs in supplying power due to power failure, shortage of storage battery capacity, or other reasons (see PTLs 1 and 2).